#ifndef TREE_MINHEAP_MINHEAP_H
#define TREE_MINHEAP_MINHEAP_H
template<typename Type> 
class MinHeap
{
public:
	MinHeap(int size):m_nMaxSize(size > defaultsize ? size : defaultsize)
		,m_pheap(new Type[m_nMaxSize]),m_ncurrentsize(0){}
	MinHeap(Type heap[],int n);		//initialize heap by a array
	~MinHeap()
	{
		delete[] m_pheap;
	}

public:
	bool Insert(const Type item);	//insert element
	bool Delete(const Type item);	//delete element
	bool IsEmpty() const
	{		
		return m_ncurrentsize == 0;
	}
	bool IsFull() const
	{
		reutrn m_ncurrentsize == m_nMaxSize;
	}
	void Print(const int start=0, int n=0);			

private:
	//adjust the elements of the child tree with the root of start from top to bottom
	void Adjust(const int start, const int end);	

private:
	static const int defaultsize = 100;
	const int m_nMaxSize;	
	Type *m_pheap;
	int m_ncurrentsize;
};

template<typename Type> 
void MinHeap<Type>::Adjust(const int start, const int end)
{
	int i = start,j = i*2+1;    //get the position of the child of i
	Type temp=m_pheap[i];
	while(j <= end)
	{    
		if(j<end && m_pheap[j]>m_pheap[j+1])
		{   //left>right
			j++;
		}
		if(temp <= m_pheap[j])
		{ //adjust over
			break;
		}
		else
		{   //change the parent and the child, then adjust the child
			m_pheap[i] = m_pheap[j];
			i = j;
			j = 2*i+1;
		}
	}
	m_pheap[i] = temp;
}

template<typename Type> 
MinHeap<Type>::MinHeap(Type heap[], int n):m_nMaxSize(n > defaultsize ? n : defaultsize)
{
		m_pheap = new Type[m_nMaxSize];
		for(int i=0; i<n; i++)
		{
			m_pheap[i] = heap[i];
		}
		m_ncurrentsize = n;
		int pos=(n-2)/2;	//Find the last child tree which has more than one element;
		while(pos>=0)
		{
			Adjust(pos, n-1);
			pos--;
		}
}

template<typename Type> 
bool MinHeap<Type>::Insert(const Type item)
{
	if(m_ncurrentsize == m_nMaxSize)
	{
		cerr<<"Heap Full!"<<endl;
		return 0;
	}
	m_pheap[m_ncurrentsize] = item;
	int j = m_ncurrentsize, i = (j-1)/2;    //get the position of the parent of j
	Type temp = m_pheap[j];
	while(j > 0)
	{   //adjust from bottom to top
		if(m_pheap[i] <= temp)
		{
			break;
		}
		else
		{
			m_pheap[j] = m_pheap[i];
			j = i;
			i = (j-1)/2;
		}
	}
	m_pheap[j] = temp;
	m_ncurrentsize++;
	return 1;
}

template<typename Type> 
bool MinHeap<Type>::Delete(const Type item)
{
	if(0 == m_ncurrentsize)
	{
		cerr<<"Heap Empty!"<<endl;
		return 0;
	}
	for(int i=0; i<m_ncurrentsize; i++)
	{
		if(m_pheap[i] == item)
		{
			m_pheap[i] = m_pheap[m_ncurrentsize-1]; //filled with the last element
			Adjust(i,m_ncurrentsize-2);     //adjust the tree with start of i
			m_ncurrentsize--;
			i=0;
		}
	}
	return 1;
}

template<typename Type> 
void MinHeap<Type>::Print(const int start, int n)
{
	if(start >= m_ncurrentsize)
	{
		return;
	}
	Print(start*2+2, n+1);  //print the right child tree

	for(int i=0; i<n; i++)
	{
		cout<<"    ";
	}
	cout<< m_pheap[start] << "--->" << endl;

	Print(start*2+1, n+1);  //print the left child tree
}

#endif